US election: Battleground states 美國2012大選：爭奪關鍵州圖表一覽

BBC News - US election: Battleground states
http://www.bbc.co.uk/news/world-us-canada-17306282
BBC中文網 - 國際新聞 - 美國2012大選：爭奪關鍵州圖表一覽
http://www.bbc.co.uk/zhongwen/trad/world/2012/10/121003_usa2012_battleground_states_map.shtml
BBC News - Obama v Romney: US election poll tracker
http://www.bbc.co.uk/news/world-us-canada-19415745